[Operating method and changer for optical module/printer module system]

ABSTRACT

A method of operating an optical module/printer module system through a changer such that either the optical module or the printer module is driven. A first module and a second module is defined such that if the first module is an optical module, the second module is a printer module and if the first module is a printer module, the second module is an optical module. The operating method includes the following steps. In step one, the changer engages with the first module and drives the first module. In step two, the changer rotates so that the changer detaches from the first module and engages with the second module. In step three, the changer drives the second module.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Taiwan applicationserial No. 91116235, filed on Jul. 22, 2002.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to an operating method and a changer foran optical module/printer module system.

More particularly, the present invention relates to an operating methodand a changer for an optical module/printer module system capable ofreducing overall drive loading.

2. Description of Related Art

Following the rapid progress in electronic technologies and developmentof multimedia techniques, most products incorporate a few functions soas to reduce spatial occupation. For example, a machine may combinevarious functions including facsimile, scanning, copying and telephoningtogether so that many applications can be performed without occupyingtoo much space.

FIG. 1 is a schematic diagram showing the operational linkage of aconventional optical module/printer module system. To integrate scanningand printing function together, a multifunction machine often has anoptical module 110 and a printer module 120. The multifunction machineis able to scan a document through the optical module 110 and print adocument through the printer module 120. The multifunction machinefurther includes a transmission mechanism 130 for driving the opticalmodule 110 and the printer module 120. The transmission mechanism 130includes an electric motor (not shown), a driving belt 132 and acoupling structure 134. The electric motor drives the driving belt 132while the coupling structure 134 is attached to the driving belt 132.The coupling structure 134 engages with the optical module 110 and theprinter module 120. Hence, the optical module 110 and the printer module120 move synchronously together when the electric motor pulls thedriving belt 132.

Using the aforementioned multifunction machine, the optical module 110must be driven to scan a document (not shown). However, through thecoupling structure 134,the printer module 120 is also driven. With suchunnecessary coupling, the electric motor needs to carry an extra load sothat power is wasted. Similarly, the optical module 110 is also drivenwhen the printing module 120 prints out a document. Hence, an extra loadis carried and power is wasted.

SUMMARY OF INVENTION

Accordingly, one object of the present invention is to provide a methodof operating an optical module/printer module system and a changer forselectively coupling with either the optical module or the printermodule such that overall driving load of a driver is reduced and poweris saved.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, theinvention provides a method of operating a multi-modular system. Eithera first module or a second module is driven by selection through amodule changer. The method of operating the multi-modular systemincludes the following steps.

In the first step, a changer is provided. The changer comprises aroller, a first lever rod and a second lever rod. The roller has a firstspiral groove and a second spiral groove. The first spiral groove andthe second spiral groove spirals around the central axis of the rolleron a perimeter surface of the roller. Depth of the first and the secondspiral groove from the perimeter surface of the roller increasesgradually but the direction of increasing depth in the second spiralgroove is opposite to the direction of increasing depth in the firstspiral groove. The roller is constrained to travel in a lineardirection. The first lever rod and the second rod are situated at thesame end along the path traveled by the roller. The roller furtherincludes a latching element on the perimeter surface of the roller. Ifthe changer joins with the first module through the latching elementinitially, the changer drives the first module. In the second step, theroller moves to one end of its travel path close to the first lever rod.In the third step, the first lever rod dips into the first spiral grooveand presses against the bottom surface of the first spiral groove sothat the roller rotates. The latching element of the roller now detachesfrom the first module and engages with the second module. In the fourthstep,the changer drives the second module forward along the travel pathof the roller. In the fifth step, the roller moves to another end of itstravel path close to the second lever rod. In the sixth step, the secondrod dips into the second spiral groove and presses against the bottomsurface of the second spiral groove so that the roller rotates. Thelatching element of the roller now detaches from the second module andengages with the first module. In the seventh step, the roller drivesthe first module forward along the travel path of the roller.

This invention also provides an alternative method of operating amulti-modular system. Either a first module or a second module is drivenby selection through a module changer. The method of operating themulti-modular system includes the following steps.

In the first step, a changer is provided. The changer comprises of aroller, a first lever rod and a second lever rod. The roller has a firstside surface and a corresponding second side surface. The roller alsohas a first spiral groove and a second spiral groove. The first spiralgroove spirals around the central axis of the roller on the first sidesurface of the roller. Depth of the first spiral groove from the firstside surface of the roller increases gradually. The second spiral groovespirals around the central axis of the roller on the second side surfaceof the roller. Depth of the second spiral groove from the second sidesurface of the roller increases gradually. The roller is constrained totravel in a linear direction. The first lever rod and the second rod aresituated at the respective opposite ends of the path traveled by theroller. The roller further includes a first latching element, a secondlatching element and a third latching element on the perimeter surfaceof the roller. If the changer joins with the first module through thefirst latching element initially, the changer drives the first module.In the second step, the roller moves to one end of its travel path closeto the first lever rod. In the third step, the first lever rod dips intothe first spiral groove and presses against the bottom surface of thefirst spiral groove so that the roller rotates in a first direction. Thefirst latching element of the roller now detaches from the first moduleand the second latching element of the roller engages with first module.In the fourth step, the roller moves to another end of the travel pathclose to the second lever rod. In the fifth step, the second lever roddips into the second spiral groove and presses against the bottomsurface of the second spiral groove so that the roller rotates in asecond direction. The second direction is just the opposite of the firstdirection. The second latching element of the roller now detaches fromthe first module and the third latching element of the roller engageswith the second module. In the sixth step, the roller drives the secondmodule forward along the travel path of the roller. In the seventh step,the roller moves to one end of its travel path close to the second leverrod. In the eighth step, the second lever rod dips into the secondspiral groove and presses against the bottom of the second spiral grooveso that the roller rotates in the second direction. The third latchingelement detaches from the second module and the first latching elementof the roller engages with the first module. In the ninth step, theroller drives the first module along the path traveled by the roller.

In the aforementioned method of operating a multi-modular system, whenthe first module is an optical module, the second module is a printermodule. Similarly, when the first module is a printer module, the secondmodule is an optical module. The first latching element, the secondlatching element and the third latching element are bump-shapestructures. When an external force is applied to the first latchingelement, the second latching element or the third latching element,these elements may retract inwards towards the interior of the roller.However, when the external force is removed, these latching elements maybounce back to their original positions. In addition, the first leverrod is fixed in position. The first lever rod dips into the first spiralgroove through the movement of the roller and the bottom section of thefirst spiral groove props against the first lever rod so that the rollerrotates. The second lever rod is also fixed in position. The secondlever rod dips into the second spiral groove through the movement of theroller and the bottom section of the second spiral groove props againstthe second lever rod so that the roller rotates.

In brief, the method of operating the optical module/printer modulesystem and the optical module/printer module system changer according tothis invention is able to reduce the loading of a driving motor andhence saves energy.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic diagram showing the operational linkage of aconventional optical module/printer module system.

FIG. 2 is a schematic diagram showing a changer driving an opticalmodule according to one preferred embodiment of this invention.

FIG. 3 is a schematic diagram showing a changer driving a printer moduleaccording to one preferred embodiment of this invention.

FIG. 4 is a magnified side view showing the coupling between the rollerof a changer and an optical module according to one preferred embodimentof this invention.

FIG. 5 is a magnified side view showing the coupling between the rollerof a changer and a printer module according to one preferred embodimentof this invention.

FIG. 6 is a cross-section view of a changer according to one preferredembodiment of this invention.

FIG. 7 is a schematic diagram showing a changer driving an opticalmodule according to another preferred embodiment of this invention.

FIGS. 8A and 8B are views on the right side of FIG. 7 showing the rollerdriven by the first lever rod when the roller has already reached afirst end of the driving belt.

FIGS. 9A and 9B are views on the left side of FIG. 7 showing the rollerdriven by the second lever rod when the roller has already reached asecond end of the driving belt.

FIGS. 10A, 10B and 10C are views on the left side of FIG. 7 showing theprocess of engaging the changer to the optical module or the printermodule.

DETAILED DESCRIPTION

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

FIG. 2 is a schematic diagram showing a changer driving an opticalmodule according to one preferred embodiment of this invention. FIG. 3is a schematic diagram showing a changer driving a printer moduleaccording to one preferred embodiment of this invention. A multifunctionstation needs to engage with an optical module 210 or a printer module220. In general, documents are scanned through the optical module 210while documents are printed through the printer module 220. Eachmultifunction station has a transmission mechanism 230 for driving theoptical module 210 and the printer module 220. The transmissionmechanism 230 typically includes an electric motor (not shown), adriving belt 240 and a changer 250. The driving belt 240 is driven bythe electric motor and the changer is fastened to the driving belt 240.The changer 250 has a latching element 262 capable of coupling witheither the optical module 210 or the printer module 220. As the electricmotor moves the driving belt 240, the optical module 210 or the printermodule 220 will move synchronously.

As shown in FIG. 2, the changer 230 is coupled to the optical module 210so that the optical module 210 moves synchronously to perform a scanningoperation when the driving belt 240 is driven by the electric motor. Toconduct a printing operation after the scanning operation, the changer250 must rotate to detach the latching element 262 of the changer 250from the optical module 210 and re-engage with the printer module 220.Hence, the printer module 220 moves synchronously to print a documentwhen the driving belt 240 is driven by the electric motor.

The following is a detailed description of the changer and itsoperation. FIG. 4 is a magnified side view showing the coupling betweenthe roller of a changer and an optical module according to one preferredembodiment of this invention. FIG. 5 is a magnified side view showingthe coupling between the roller of a changer and a printer moduleaccording to one preferred embodiment of this invention. FIG. 6 is across-section view of a changer according to one preferred embodiment ofthis invention. As shown in FIGS. 4, 5 and 6, the changer includes afirst lever rod 252, a second lever rod 254, a roller 260 and a pair ofcarrier blocks 270. Each carrier block 270 includes a latching structure272. Through the latching structure 272, the carrier block 270 isfastened to the driving belt 240. The roller 260 is bracketed within thecarrier blocks 270 but is free to rotate within the carrier blocks 270.The roller 260 has a latching element 262 such as a bump attached to theperimeter surface 263 of the roller 260 for engaging with either theoptical module 210 or the printer module 220. The roller 260 furtherincludes a first spiral groove 264. The first spiral groove 264 spiralsaround the central axis 268 on a side surface 261 of the roller 260 anddepth of the first spiral groove 264 increases gradually in a clockwisedirection. The roller 260 further includes a second spiral groove 266.The second spiral groove 266 spirals around the central axis 268 on aside surface 261 of the roller 260 and depth of the second spiral groove266 increases gradually in an anti-clockwise direction. In addition, thecarrier block 270 has a hole 274 through which the first lever rod 252may pass into the first spiral groove 264 and the second lever rod 254may pass into the second spiral groove 266.

As shown in FIG. 4, the changer 250 and the optical module 210 arecoupled together so that the optical module 210 moves synchronously whenthe driving belt 240 is driven by the electric motor. To conduct aprinting operation after the scanning operation, the roller 260 must berotated. The driving belt 240 drives the roller 260 to the rightmostposition as shown in FIG. 6 before stopping. The first lever rod 252protrudes out, dips into the first spiral groove 264 and presses againstthe bottom surface of the first spiral groove 264 so that the roller 260rotates in an anti-clockwise direction 292 for a total of 180°. Hence,the latching element 262 of the roller 260 detaches from the opticalmodule 210 and re-engages with the printer module 220 in a configurationas shown in FIG. 5. Ultimately, the printer module 220 is able to movesynchronously and print out documents when the driving belt 240 isdriven by the electric motor. To conduct a scanning operation afterprinting, the changer 250 must rotate. The driving belt 240 drives theroller 260 to the rightmost position as shown in FIG. 6 before stopping.The second lever rod 254 protrudes out, dips into the second spiralgroove 266 and presses against the bottom surface of the second spiralgroove 266 so that the roller 260 rotates in a clockwise direction 294for a total of 180°. Hence, the latching element 262 of the roller 260detaches from the printer module 220 and re-engages with the opticalmodule 210 in a configuration as shown in FIG. 4. Thus, the opticalmodule 210 is able to move synchronously and scan documents when thedriving belt 240 is driven by the electric motor. The aforementionedsteps may be repeated to switch between scanning and printing.

Using the changer 250 as shown in FIGS. 2 to 6, the electric motor onlyhas to drive the optical module 210 in a scanning operation. Similarly,the electric motor only has to drive the printer module 220 in aprinting operation. Ultimately, overall loading of the electric motorfor driving the optical module 210 and the printer module 220 is greatlyreduced.

The embodiment of this invention is not limited to the aforementionedstructure. The first lever rod and the second lever rod may bepositioned on the left side of the driving belt so that switchingbetween the optical module and the printer module may occur when theroller moves to the leftmost side.

Furthermore, depth of the second spiral groove may gradually increase inan anti-clockwise direction while depth of the first spiral grooveincreases in a clockwise direction. With this arrangement, the rollerwill rotate in the anti-clockwise direction when the second lever roddips into the second spiral groove and presses against the bottomsurface. Meanwhile, the latching element of the roller will detach fromthe optical module and engage with the printer module. Similarly, whenthe first lever rod dips into the first spiral groove and pressesagainst the bottom surface, the roller will rotate in a clockwisedirection. The latching element of the roller will detach from theprinter module and re-engage with the optical module.

In the aforementioned method, the lever rods must be driven by anelectric motor so that the lever rod moves forward to rotate the rollerand switch between the optical module and the printer module. However,this is by no means the only the method of switching between the opticalmodule and the printer module according to this invention.

FIG. 7 is a schematic diagram showing a changer driving an opticalmodule according to another preferred embodiment of this invention. Eachmultifunction station has a transmission mechanism for driving anoptical module 310 and a printer module 320. The transmission mechanismtypically includes an electric motor (not shown), a driving belt 340 anda changer 350. The changer 350 at least includes a roller 360 and acarrier block 370. The carrier block 370 has a fastening element 372 forfastening the carrier block 370 to the driving belt 340. The roller 360is enclosed within the carrier block 370 and is able to rotate insidethe carrier block 370. Hence, through the driving belt 340, the carrierblock 370 and the roller 360 may move along a third direction 396 and afourth direction 398. The roller 360 has a first latching element 362, asecond latching element 364 and a third latching element 366. The firstlatching element 362, the second latching element 364 and the thirdlatching element 366 all have a bump-shape structure attached to theperimeter surface 363 of the roller 360. The latching elements (362,364, 366) rotate along with the roller 360 to carry out all thenecessary switching action between the optical module 310 and theprinter module 320. In addition, the first latching element 362, thesecond latching element 364 and the third latching element 366 can beretractable. In other words, each of the latching elements (362, 364,366) may retract into the interior of the roller 360 when an externalforce is applied. As soon as the external force is removed, the latchingelements may bounce back into their respective original state. The firstlatching element 362 and the second latching element 364 may engage withthe optical module 310 and the third latching element 366 may engagewith the printer module 320. Detailed description of these latchingmechanisms is further explained below.

The changer 350 further includes a first lever rod 352 and a secondlever rod 354. The first lever rod 352 and the second lever rod 354 arelocated at the respective ends such as a first end 342 and a second end344 of the driving belt 340. When the changer 350 is pulled to the firstend 342 or the second end 344 of the driving belt 340 and engaged withthe first lever rod 352 or the second lever rod 354, the roller 360 maybe driven into rotation by corresponding lever rods. The mechanism forrotating the roller 360 is explained in more detail below.

FIGS. 8A and 8B are views on the right side of FIG. 7 showing the rollerdriven by the first lever rod when the roller has already reached afirst end of the driving belt. As shown in FIGS. 7, 8A and 8B, theroller 360 has a first spiral groove 365 that spirals on one sidesurface 361 of the roller around the roller axis 368. Depth of the firstspiral groove 365 on the side surface 361 of the roller 360 increasesgradually along a first direction 392. Position of the first lever rod352 must correspond to the position of the first spiral groove 365. Whenthe roller 360 rotates continuously towards a third direction 396, thefirst lever rod 352 passes through a first hole 374 in the carrier block370 and dips into the first spiral groove 365. The first lever rod 352presses against the bottom section of the first spiral groove 365leading to a state as shown in FIG. 8A. The first lever rod 352 is fixedin position. Hence, through the continuous movement towards the thirddirection 396 of the roller 360, the first lever rod 352 is pressedagainst the bottom section of the first spiral groove 365 so that theroller 360 moves towards a second direction 394 as shown in FIG. 8B. Inaddition, by controlling the distance traveled by the roller 360 in thethird direction 396, the angle of rotation of the roller 360 towards thesecond direction 394 is set.

FIGS. 9A and 9B are views on the left side of FIG. 7 showing the rollerdriven by the second lever rod when the roller has already reached asecond end of the driving belt. As shown in FIGS. 7, 9A and 9B, theroller 360 has a second spiral groove 367 that spirals on one sidesurface 369 of the roller 360 around the roller axis 368. Depth of thesecond spiral groove 367 on the side surface 369 of the roller 360increases gradually along the second direction 394. Position of thesecond lever rod 354 must correspond to the position of the secondspiral groove 367. When the roller 360 rotates continuously towards afourth direction 398, the first lever rod 352 passes through a secondhole 376 in the carrier block 370 and dips into the second spiral groove367. The second lever rod 354 presses against the bottom section of thesecond spiral groove 367 leading to a state as shown in FIG. 9A. Thesecond lever rod 352 is fixed in position. Hence, through the continuousmovement towards the fourth direction 398 of the roller 360, the secondlever rod 354 is pressed against the bottom section of the second spiralgroove 367 so that the roller 360 moves towards the first direction 392as shown in FIG. 9B. In addition, by controlling the distance traveledby the roller 360 in the fourth direction 398, the angle of rotation ofthe roller 360 towards the first direction 392 is set.

FIGS. 10A, 10B and 10C are views on the left side of FIG. 7 showing theprocess of engaging the changer to the optical module or the printermodule. If the roller 360 is engaged to the optical module 310 throughthe first latching element 362 initially as shown in FIG. 10A, theoptical module 310 is driven to carry out normal scanning operations.

To carry out a printing operation, the roller 360 must detach from theoptical module 310 and re-engage with the printer module 320. First, theroller 360 moves to the first end 342 of the driving belt 340. Due topressure on the first spiral groove 365 by the first lever rod 352 (asshown in FIGS. 8A and 8B), the roller 360 rotates in the seconddirection 394. At this moment, the first latching element 362 detachesfrom the optical module 310 and the second latching element 364re-engages with the optical module 310 to form a configuration as shownin FIG. 10B. The second latching element 364 is somewhere along thedirection of extension of the driving belt 360 and separates from thefirst latching element 362 by a distance. The distance of separationbetween the second latching element 364 and the first latching element362 is roughly equal to the distance the roller 360 travels towards thethird direction 396 after the optical module detaches from the firstlatching element 362 and re-engages with the second latching element364. Thereafter, the roller 360 moves to the second terminal 344 of thedriving belt 340. Due to pressure on the second spiral groove 367 by thesecond lever rod 354 (as shown in FIGS. 9A and 9B), the roller 360rotates in the first direction 392. At this moment, the second latchingelement 364 detaches from the optical module 310 and the third latchingelement 366 re-engages with the printer module 320 to form aconfiguration as shown in FIG. 10C. Hence, the printer module 320 maycarry out printing jobs.

If a user wishes to switch from engaging with the printer module 320 tothe optical module 310 for conducting scanning tasks, the roller 360moves to the second end 344 of the driving belt 340. Due to pressure onthe second spiral groove 367 by the second lever rod 354 (as shown inFIGS. 9A and 9B), the roller 360 rotates in the first direction 392. Atthis moment, the third latching element 366 detaches from the printermodule 320 and the first latching element 362 re-engages with theoptical module 310 to form a configuration as shown in FIG. 10A. Hence,the optical module 310 may carry out scanning operations.

In the aforementioned process of switching between the optical module310 and the printer module 320, the first latching element 362, thesecond latching element 364 and the third latching element 366 all havea retractable mechanism. Hence, as the roller 360 rotates, the latchingelements (362, 364, 366) may retract into the interior of the roller 360when made to contact with casing of either the optical module 310 or theprinter module 320. With this arrangement, the whereabouts of the firstlatching element 362, the second latching element 364 and the thirdlatching element 366 have little effect on the rotation of the roller360. When the first latching element 362, the second latching element364 or the third latching element 366 no longer touches the casing ofthe optical module 310 or the printer module 320, the latching elementsprings back to its former configuration. The first latching element 362or the second latching element 364 may click into a latching hole 312 onthe optical module 310. When the driving belt 340 moves to drive theroller 360, the optical module 310 can move synchronously. The thirdlatching element 366 may click into a latching hole 322 on the printermodule 320. Hence, when the driving belt 340 moves to drive the roller360, the printer module 320 can move synchronously.

In the aforementioned changer, both the first lever rod 352 and thesecond lever rod 354 are fixed in position. Therefore, the changer has asimpler structural design than a conventional changer with movable firstand second lever rod.

Furthermore, this invention may also utilize the first latching elementand the second latching element for joining the roller and the printermodule together while the third latching element is used for joining theroller and the optical module together.

In summary, the optical module/printer module changer and the method ofoperating the optical module/printer module system according to thisinvention reduces overall loading of driving electric motor and hencesaves electrical energy.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A method of operating an optical module/printer module system thatuses a changer to drive either the optical module or the printer module,wherein a first module and a second module are defined such that if theoptical module is the first module, the printer module is the secondmodule and if the printer module is the first module, the optical moduleis the second module, the method comprising the steps of: the firstmodule couples with the changer so that the changer is able to drive thefirst module; the changer rotates so that the changer detaches from thefirst module and engages with the second module; and the changer drivesthe second module.
 2. The operating method of claim 1, wherein thechanger includes a lever rod and a roller, the roller has a spiralgroove on a side surface that spirals around the central axis of theroller, depth of the groove increases gradually, and on rotating thechanger, the lever rod dips into the spiral groove and presses againstthe bottom surface so that the roller rotates leading to the detachmentof the first module from a latching element on the roller and engagementof the latching element with the second module.
 3. The operating methodof claim 2, wherein depth of the spiral groove increases gradually in aclockwise direction.
 4. The operating method of claim 2, wherein depthof the spiral groove increases gradually in an anti-clockwise direction.5. The operating method of claim 2, wherein the roller has at least alatching element on the perimeter surface of the roller through whichthe roller latches either with the first module or the second module. 6.The operating method of claim 2, wherein the latching element includes abump-shape structure.
 7. The operating method of claim 5, wherein thelatching element retracts into the interior of the roller when anexternal force is applied to the latching element and the latchingelement springs back to its original position when the external force isremoved.
 8. The operating method of claim 2, wherein the lever rod isfixed in position and the roller rotates by moving the roller towardsthe lever rod so that the end of the lever rod presses against thebottom section of the spiral groove.
 9. The operating method of claim 2,wherein the lever rod is movable and the roller rotates when the leverrod moves into the spiral groove and presses against the bottom sectionof the spiral groove.
 10. A changer for driving a first module or asecond module, the changer comprising: a roller having at least alatching element for latching with either the first module or the secondmodule, wherein the roller further includes a first spiral groove on aside surface of the roller and the first spiral groove spirals aroundthe central axis of the roller such that depth of the first spiralgroove increases gradually, and the roller also includes a second spiralgroove on another side surface of the roller and the second spiralgroove spirals around the central axis of the roller such that depth ofthe second spiral groove increases gradually; a first lever rod fordipping into the first spiral groove and pressing against the bottomsurface of the first spiral groove; and a second lever rod for dippinginto the second spiral groove and pressing against the bottom surface ofthe second spiral groove.
 11. The changer of claim 10, wherein the firstspiral groove and the second spiral groove are located on the same sidesurface of the roller, the direction of increasing depth for the secondspiral groove is opposite to the direction of increasing depth for thefirst spiral groove, and hence the direction of rotation of the rollerwhen the first lever rod dips into the first spiral groove is oppositeto the direction of rotation of the roller when the second lever roddips into the second spiral groove.
 12. The changer of claim 10, whereinthe roller moves in a straight line and the first lever rod and thesecond lever rod are located at the same end of the traveling pathway ofthe roller.
 13. The changer of claim 10, wherein the roller includes afirst side surface and a corresponding second side surface, the firstspiral groove is located on the first side surface of the roller whilethe second spiral groove is located on the second side surface of theroller, and the direction of rotation of the roller when the first leverrod dips into the first spiral groove is opposite to the direction ofrotation of the roller when the second lever rod dips into the secondspiral groove.
 14. The changer of claim 10, wherein the roller moves ina straight line and the first lever rod and the second lever rod arelocated at the opposite end of the traveling pathway of the roller. 15.The changer of claim 10, wherein the first module is an optical moduleand the second module is a printer module.
 16. The changer of claim 10,wherein the first module is a printer module and the second module is anoptical module.
 17. The changer of claim 10, wherein the latchingelement is a bump-shape structure located on the perimeter surface ofthe roller.
 18. The changer of claim 10, wherein the latching element islocated on the perimeter surface of the roller and the latching elementretracts into the interior of the roller when an external force isapplied to the latching element and the latching element springs back toits original position when the external force is removed.
 19. Thechanger of claim 10, wherein the first lever rod is fixed in positionand the roller rotates by moving the roller towards the first lever rodso that the end of the first lever rod presses against the bottomsection of the first spiral groove.
 20. The changer of claim 10, whereinthe second lever rod is fixed in position and the roller rotates bymoving the roller towards the second lever rod so that the end of thesecond lever rod presses against the bottom section of the second spiralgroove.
 21. The changer of claim 10, wherein the first lever rod ismovable and the roller rotates when the first lever rod moves into thefirst spiral groove and presses against the bottom section of the firstspiral groove.
 22. The changer of claim 10, wherein the second lever rodis movable and the roller rotates when the second lever rod moves intothe second spiral groove and presses against the bottom section of thesecond spiral groove.
 23. A changer for driving a first module and asecond module, the changer comprising: a roller having a latchingelement thereon, wherein the roller latches with either the first moduleor the second module through the latching element, the roller furtherincludes a spiral groove on a side surface, the spiral groove spiralsaround a central axis of the roller and depth of the spiral grooveincreases gradually; and a lever rod capable of dipping into the spiralgroove and pressing against the bottom surface of the spiral groove. 24.The changer of claim 23, wherein the first module is an optical moduleand the second module is a printer module.
 25. The changer of claim 23,wherein the first module is a printer module and the second module is anoptical module.
 26. The changer of claim 23, wherein depth of the spiralgroove increases in a clockwise direction.
 27. The changer of claim 23,wherein depth of the spiral groove increases in an anti-clockwisedirection.
 28. The changer of claim 23, wherein the latching element isa bump-shape structure attached to the perimeter surface of the roller.29. The changer of claim 23, wherein the latching element is located onthe perimeter surface of the roller and the latching element retractsinto the interior of the roller when an external force is applied to thelatching element and the latching element springs back to its originalposition when the external force is removed.
 30. The changer of claim23, wherein the lever rod is fixed in position and the roller rotates bymoving the roller towards the first lever rod so that the end of thefirst lever rod presses against the bottom section of the first spiralgroove.
 31. The changer of claim 23, wherein the lever rod is movableand the roller rotates when the lever rod moves into the spiral grooveand presses against the bottom section of the spiral groove.
 32. Amethod of operating a multi-module system that uses a changer to driveeither a first module or a second module, the method comprising thesteps of: step one: providing a changer having: a first lever rod; asecond lever rod; a roller having a latching element, wherein the rollerhas a first spiral groove on a side surface of the roller and the firstspiral groove spirals around the central axis of the roller such thatdepth of the first spiral groove increases gradually, and the rolleralso has a second spiral groove on the side surface of the roller andthe second spiral groove spirals around the central axis of the rollersuch that depth of the second spiral groove increases gradually, depthof the first spiral groove increases in a direction opposite to thesecond spiral groove, the roller travels in a straight line, the firstlever rod and the second lever rod are positioned at the same end of thetraveling path of the roller, and the roller further includes a latchingelement attached to the perimeter surface of the roller; wherein if thelatching element on the roller of the changer engages with the firstmodule initially, the changer is able to drive the first module; steptwo: the roller moves to one end of its traveling path close to thefirst lever rod; step three: the first lever rod dips into the firstspiral groove and presses against the bottom surface of the first spiralgroove so that the roller rotates, the latching element on the rollerdetaches from the first module and re-engages with the second module;step four: the roller moves and pulls the second module along thetraveling path of the roller; step five: the roller moves to another endof the traveling path of the roller close to the second lever rod; stepsix: the second lever rod dips into the second spiral groove and pressesagainst the bottom surface of the second spiral groove so that theroller rotates, the latching element on the roller detaches from thesecond module and re-engages with the first module; and step seven: theroller moves and pull the first module along the traveling path of theroller.
 33. The method of claim 32, wherein the first module is anoptical module and the second module is a printer module.
 34. The methodof claim 32, wherein the first module is a printer module and the secondmodule is an optical module.
 35. The method of claim 32, wherein thelatching element is a bump-shape structure.
 36. The method of claim 32,wherein the first lever rod is movable and the roller rotates when thefirst lever rod moves into the first spiral groove and presses againstthe bottom section of the first spiral groove.
 37. The method of claim32, wherein the second lever rod is movable and the roller rotates whenthe second lever rod moves into the second spiral groove and pressesagainst the bottom section of the second spiral groove.
 38. A method ofoperating a multi-module system that uses a changer to drive either afirst module or a second module, the method comprising the steps of:step one: providing a changer having: a first lever rod; a second leverrod; a roller having a latching element, wherein the roller has a firstside surface and a corresponding second side surface, the roller alsohas a first spiral groove and a second spiral groove, the first spiralgroove is on the first side surface of the roller and spirals around thecentral axis of the roller such that depth of the first spiral grooveincreases gradually, the second spiral groove is on the second sidesurface of the roller and spirals around the central axis of the rollersuch that depth of the second spiral groove increases gradually, theroller travels in a straight line, the first lever rod and the secondlever rod are positioned at the opposite end of the traveling path ofthe roller, and the roller further includes a first latching element, asecond latching element and a third latching element attached to theperimeter surface of the roller; wherein if the first latching elementon the roller of the changer engages with the first module initially,the changer is able to drive the first module; step two: the rollermoves to one end of its traveling path close to the first lever rod;step three: the first lever rod dips into the first spiral groove andpresses against the bottom surface of the first spiral groove so thatthe roller rotates in a first direction, the first latching element onthe roller detaches from the first module and the second latchingelement re-engages with the first module; step four: the roller moves toanother end of its traveling path close to the second lever rod; stepfive: the second lever rod dips into the second spiral groove andpresses against the bottom surface of the second spiral groove so thatthe roller rotates in a second direction just opposite to the firstdirection, the second latching element on the roller detaches from thefirst module and the third latching element on the roller re-engageswith the second module; step six: the roller moves and pulls the secondmodule along the traveling path of the roller; step seven: the rollermoves to another end of its traveling path close to the second leverrod; step eight: the second lever rod dips into the second spiral grooveand presses against the bottom surface of the second spiral groove sothat the roller rotates in the second direction, the third latchingelement of the roller detaches from the second module and the firstlatching element of the roller re-engages with the first module; andstep nine: the roller moves and pulls the first module along thetraveling path of the roller.
 39. The method of claim 38, wherein thefirst module is an optical module and the second module is a printermodule.
 40. The method of claim 38, wherein the first module is aprinter module and the second module is an optical module.
 41. Themethod of claim 38, wherein the first latching element has a bump-shapestructure located on the perimeter surface of the roller and that thefirst latching element retracts into the interior of the roller when anexternal force is applied to the first latching element and the firstlatching element springs back to its original position when the externalforce is removed.
 42. The method of claim 38, wherein the secondlatching element has a bump-shape structure located on the perimetersurface of the roller and the second latching element retracts into theinterior of the roller when an external force is applied to the secondlatching element and the second latching element springs back to itsoriginal position when the external force is removed.
 43. The method ofclaim 38, wherein the third latching element has a bump-shape structurelocated on the perimeter surface of the roller and the third latchingelement retracts into the interior of the roller when an external forceis applied to the third latching element and the third latching elementsprings back to its original position when the external force isremoved.
 44. The method of claim 38, wherein the first lever rod ismovable and the roller rotates when the first lever rod moves into thefirst spiral groove and presses against the bottom section of the firstspiral groove.
 45. The method of claim 38, wherein the second lever rodis movable and the roller rotates when the second lever rod moves intothe second spiral groove and presses against the bottom section of thesecond spiral groove.